external hd read only after snow leopard install

Hi, I installed snow leopard and now my permissions for my external drives (mac formatted) are now read-only. It wont let me change the permission, or change owner, even when I go through root account (regular account is an admin). I already repaired permissions on my mac hd in a vain attempt to see if that would help, but it didn't.

I then tried the chmod command in terminal
sudo chmod -R u+rwX /Volumes/"myexternaldrivename"
but all i get is this for every file on the drive.
chmod: Unable to change file mode on /Volumes/Aaron's Big External/music/iTunes/iTunes Music/Disturbed/Ten Thousand Fists (Bonus Video Version)/Video - Stricken.mp4: Permission denied

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